PET vs. PP Plastic Water Cups: Core Parameter Comparison

1. Comparison of Basic Material Properties

1.1 Molecular Structure and Chemical Properties

• PET: The molecule is a linear saturated polyester, formed by the polycondensation of terephthalic acid (PTA) and ethylene glycol (EG). The molecular chain contains a large number of ester groups and benzene rings, possessing both rigidity and toughness. It has good chemical stability, is resistant to most organic solvents and concentrated nitric acid, but is easily corroded by strong alkalis, and has excellent water resistance.
• PP: The main molecular chain consists of carbon-carbon single bonds, with methyl groups in the side chains. The molecular chain has high regularity, with a crystallinity of 60%-70%. It is a white, waxy, transparent, and lightweight material. It is resistant to acids, alkalis, and organic solvents, but not resistant to strong oxidizing substances such as nitric acid and mineral oil.

1.2 Production Raw Materials and Industrial Chain

• PET: The raw materials are purified terephthalic acid (PTA) and ethylene glycol (MEG). In 2023, the global PTA production capacity exceeded 90 million tons, with China accounting for over 65% (dominated by Hengli Petrochemical, Rongsheng Petrochemical, etc.). PTA is produced by the oxidation of p-xylene; ethylene glycol production capacity is approximately 18 million tons/year, with both coal-based and petroleum-based processes coexisting, ensuring a stable raw material supply for large-scale production.
• PP: The raw materials come from petroleum and natural gas. Propylene monomers are obtained from refineries or ethylene cracking units, and then polymerized through catalysts to form long molecular chains. In 2023, China's total PP production capacity exceeded 35 million tons (accounting for 38% of the global total), of which the oil-based route accounted for 68% and the coal-based route accounted for 32%, with continuous expansion of production capacity.

1.3 Market Position and Capacity Development

• PET: Focuses on beverage packaging (carbonated drinks, mineral water, fruit juices, etc.), dominating the market due to its high transparency and gas barrier properties. In 2023, the total domestic PET bottle production capacity reached 18.5 million tons (a year-on-year increase of 6.3%), and the production of bottle-grade PET reached 15.07 million tons in 2024 (a year-on-year increase of 14.25%). It is expected that modified materials such as PETG will drive annual production to 19.5 million tons in the future, with food-contact grade products accounting for 89%.
• PP: Primarily used in hot beverage packaging and microwaveable food containers, expanding its market share based on its heat resistance and cost-effectiveness advantages. It is projected that China's annual PP production capacity will exceed 38 million tons in 2025 and reach over 50 million tons in 2030 (with an average annual compound growth rate of 5.8%); in the first quarter of 2025, there were 48 key enterprises producing transparent PP plastic water cups (with an annual capacity of over 5,000 tons), with a total designed capacity of 2.167 million tons (a year-on-year increase of 8.3%).

2. In-depth Cost-Benefit Comparison

2.1 Raw Material Cost Analysis

• Price and Density: In early 2026, the price of PP (filament grade) was 6376.67 yuan/ton, and the price of PET was 6075 yuan/ton. While PP appears slightly higher, the density of PET (1.35-1.4 g/cm³) is higher than that of PP (0.9-0.915 g/cm³) – 1 kg of PET can produce 109 containers, while 1 kg of PP can produce 161 containers (PP containers weigh 31% less than PET).  Therefore, the actual material cost of PET may be lower for the same volume.
• Price Volatility: PET prices are relatively stable, with the operating range for polyester bottle chips in 2025 being 5388-6447 yuan/ton (a fluctuation range of 19.7%); PP fluctuates more dramatically, with the lowest price for filament-grade PP in North China falling to 5920 yuan/ton in December 2025, requiring stricter cost control.
• Recycled Material Advantage: In 2023, the cost of food-grade rPET decreased to 1.2 times that of virgin PET, and it is expected to achieve a price inversion in 2027, providing PET with a competitive advantage in cost-sensitive applications. 

2.2 Processing Cost Comparison

• PET processing: Requires stringent conditions, with injection molding barrel temperatures of 240-280℃ (nozzle temperature 5-10℃ lower to prevent drooling), and raw materials need to be dried at 140-150℃ for 4 hours (moisture content ≤0.02%). Equipment investment and energy consumption are higher; it relies on injection molding-stretching-blow molding processes, requiring precision steel molds (development cycle of 2 months, single set cost of 200,000-300,000 RMB, 10-20 times that of thermoforming molds), but for large-scale production (1 million plastic water cups), the unit cost is 0.1-0.2 RMB lower than thermoforming.
• PP processing: Simpler, with a melting temperature of approximately 160℃ (lower than PET's 245℃), a wide processing window, lower equipment requirements, and less energy consumption; it can use either thermoforming or injection molding processes (injection molding solves the uneven wall thickness problem of thermoformed clear plastic cups with lids). Taking milk tea plastic water cups as an example, the total cost per unit is approximately 0.1575 RMB (including raw materials, energy consumption, labor, etc.), demonstrating a significant cost advantage.

2.3 Comprehensive Cost Assessment

• Cost composition: Taking a 200-gram trash can as an example, the PP material cost is 4.5 RMB (including 17,000 RMB/ton for raw materials, 60,000 RMB for molds, 500 RMB for auxiliary materials and electricity, and 1 RMB/person for labor); PET enjoys bulk discounts in large-scale production, and the biaxial stretching process improves strength and barrier properties, reducing unit cost.
• Transportation and environmental costs: PP has a lower density, resulting in lower transportation costs for products of the same volume; the EU will impose a tax of 800 euros per ton on non-recyclable plastics starting in 2025 (increasing the cost per unit by 0.08-0.12 euros), and global carbon footprint certification costs will be 120,000-180,000 US dollars in 2026 (accounting for 35%-42% of the average annual profit of small and medium-sized manufacturers), and PET's recyclability advantage can reduce environmental costs.
• Long-term trend: Bio-based plastics are 15-25% more expensive than traditional plastics, but the premium is expected to decrease to 10-15% by 2026 and within 5-10% by 2030, gradually narrowing the cost gap between the two.

 

3. Comprehensive Environmental Performance Assessment

3.1 Life Cycle Environmental Impact

• Comparative data: Research commissioned by Milliken and conducted by Sphera shows that, for the same weight (9.1g), the environmental impact of PP during landfill/incineration is lower than that of virgin PET, while the two are similar during recycling. In terms of carbon emissions, virgin PET emits 2.39 tons/ton, and recycled PET emits 1.15 tons/ton (lower than corrugated cardboard at 6.14 tons/ton and PLA at 2.7 tons/ton), with 100% recycled PET reducing carbon emissions by 50%.
• Recycling emission reduction effect: In 2019, Japan's designated PET bottle recycling resulted in a total CO₂ emission of 2059 kilotons (3528 kilotons without recycling, a reduction of 42%); compared to virgin fibers, recycled PET fibers reduce global warming potential by 32.09 kg CO₂ equivalent and acidification potential by 0.37 kg SO₂ equivalent per 100 kg, verifying the environmental advantages of PET recycling.

3.2 Comparison of Recycling Performance

• Recycling rate: The global PET bottle recycling rate is 50-60% (15% in the US in 2019), while PP is only 20% (3% in the US in 2019), a significant difference.
• PET recycling technology: Enzymatic depolymerization technology is expected to be commercialized by 2025 (increasing the recycling rate from 75% to 92%), intelligent sorting + multi-spectral recognition achieves a bottle flake purity of 99.96%, and supercritical fluid technology improves the melt strength of recycled materials to 97% of virgin materials; China's Wanhua Chemical's closed-loop depolymerization technology (98% depolymerization efficiency, 99.9% terephthalic acid purity) has entered pilot testing, and Kingfa Technology's deep cleaning system controls recycled PET impurities below 30 ppm (meeting FDA standards).
• PP recycling challenges: PP molecules are easily degraded by light, heat, and oxygen (turning yellow and brittle), and recycled PP is often used in lower-grade applications (such as storage containers); Milliken and PureCycle are collaborating to develop patented technology that can restore PP to "near-virgin" quality after separating contaminants, gradually overcoming technological bottlenecks.

3.3 Environmental Policy Adaptability

• Chinese policies: In September 2025, the "Guidelines for the Design of Recyclable Plastics" were released, requiring labels to be compatible with hot washing, inks to be biodegradable, and containers to have simplified assembly (effective February 2026). "Separable bottle labels" can increase the purity of PET flakes by more than 30%; a nine-ministry plan in 2024 requires that by 2026, the proportion of recyclable design for daily-use plastics should be ≥90%, and the use of disposable non-degradable mouthwash plastic water cups in hotels and other settings should be reduced by 50%.
• International policies: The EU requires that from 2025, the recycled content of PET bottles should be ≥25% (≥30% by 2030), and disposable beverage bottles should have ≥30% recycled content by 2025 (50%-65% by 2040); Germany and South Korea are also implementing mandatory recycled content requirements; Vietnam will impose an environmental tax on plastic packaging from 2025 (recyclable film is taxed at 8%, and those with over 30% domestically produced recycled content are exempt).
• Material adaptability: PET's high recycling rate and mature technology make it easier to meet policy requirements, while PP faces greater challenges due to its recycling shortcomings.

 

4. Physical Performance System Comparison

4.1 Mechanical Properties

• PET: Tensile strength is 1.5-2 times that of PP, excellent creep resistance (not easily deformed at high temperatures), impact strength is 3-5 times that of ordinary films, and room temperature falling ball impact strength is 100-150 cm·kg/cm²; high rigidity but high brittleness, excellent bottle neck thread accuracy (suitable for high-speed filling lines), adding EVA can increase the notched impact strength from 4-7 kJ/m² to 15 kJ/m².
• PP: Outstanding flexibility and fatigue resistance, leaves white marks after folding, can be bent 10⁶ times without damage ("hundred-fold plastic"); excellent stress crack resistance (can be designed for foldable soft bags), slightly soft and less brittle, but easily becomes brittle at low temperatures, so attention should be paid to the application environment temperature.

4.2 Thermal Properties

• PET: Melting point 250-260℃, but heat distortion temperature (HDT) is only 70℃ (0.45MPa load), glass transition temperature 70-80℃, long-term use temperature 120℃ (short-term 150℃); only suitable for -40℃ to 70℃ (cold drinks, refrigeration), easily deformed at high temperatures and may release harmful substances, not suitable for hot drinks.
• PP: Melting point 165℃, heat distortion temperature 110℃, long-term use temperature 100-110℃ (the only microwaveable plastic), does not deform at 150℃ when not under stress; operating temperature -30℃ to 140℃, can withstand 100-130℃ hot drinks (does not deform or release harmful substances when brewed with boiling water), significantly better thermal stability than PET.

4.3 Barrier Properties

• PET: Excellent barrier properties against oxygen, water, and carbon dioxide, oxygen permeability is only 1/10 of PP, which can extend the shelf life of easily oxidized drugs; low water absorption, stable dimensions, suitable for carbonated beverages, fruit juices and other applications requiring high barrier properties, accounting for more than 70% of PET bottle applications, and lightweight design can reduce material usage.
• PP: Generally has average barrier properties, with a high water vapor transmission rate, requiring aluminum film coating or co-extrusion process for enhancement; excellent chemical stability (acid and alkali resistant), suitable for low-barrier applications such as yogurt and condiments. Multi-layer composite structures will increase costs.

4.4 Optical and Hygienic Properties

• Optical properties: PET has five-star transparency (glass-like texture, high gloss), suitable for displaying contents; PP is translucent to opaque (matte/cloudy), adding transparent nucleating agents can reduce the haze of 1mm thin sheets from 40% to 6%-7%, and the fifth-generation transparent agent Milad Glix 9000 can reduce precipitation and improve compatibility.
• Hygienic properties: Both meet food contact standards. PET is non-toxic and odorless but not heat-resistant (may release harmful substances above 60℃, not suitable for repeated use); PP is safer, does not release bisphenol A or plasticizers under normal use, is wear-resistant and impact-resistant (long service life), PP (No. 5) can be reused for a long time, while PET (No. 1) is recommended for single use (prone to bacterial growth).

 

5. Comparison of Processing Technologies

5.1 Applicability of Molding Processes

• PET: The mainstream process is injection molding-stretching-blow molding (first injection molding of preforms, then heating to 90-110℃, followed by longitudinal stretching + high-pressure air transverse stretching, and rapid cooling and shaping). Molecular orientation improves strength and barrier properties; thermoforming is also possible (high transparency, good rigidity, but only suitable for contents below 60℃).
• PP: More process options are available, including thermoforming (forming after extrusion of sheet material) or injection molding (solving the problem of uneven wall thickness); supports extrusion blow molding (tubular preform fused at the bottom, then stretched and blown), injection blow molding (suitable for complex bottle shapes), and thermoforming (thermoplastic sheet heated and pressed onto a mold), with low equipment requirements and suitability for large-scale production. 

5.2 Processing Parameter Requirements

• PET injection molding: Barrel temperature 240-280℃ (to prevent decomposition and insufficient filling), mold temperature 30-85℃ (non-crystalline products ≤70℃), injection pressure up to 160MPa (thin-walled), holding pressure 50-70% of injection pressure (to prevent shrinkage); requires staged injection control (low speed to avoid cold slugs, high speed to fill the mold and maintain fluidity).
• PP injection molding: Melting temperature approximately 160℃, wide processing window, clamping force calculated as projected area × 0.3-0.4 tons/cm²; significantly lower energy consumption than PET, lower heating costs, suitable for cost-sensitive production.

5.3 Secondary Processing Capabilities

• PET: Excellent surface polarity, allows screen printing, UV printing, and heat transfer printing without pretreatment (strong ink adhesion, vibrant colors, fine patterns), supports printing on both sides (multi-color support), suitable for transparent boxes and cylindrical products; can be coated with anti-fog/anti-static coatings, and compounded with aluminum foil and paper (to expand barrier properties and application scenarios).
• PP: Strong surface inertness, printing requires corona treatment (to increase surface tension), color gloss is slightly inferior to PET, but printing is stable (suitable for large-scale production); poor coating adhesion (requires special primer), limited compounding performance, supports hot die-cutting and straight-line box gluing, not suitable for lamination or high-frequency welding; plasma coating or chemical primers can improve printing and coating effects, heat transfer printing can achieve metal/foil effects.

6. Application Scenarios and Market Positioning Analysis

6.1 Comparison of Applicable Scenarios

• PET plastic water cups: Focus on "aesthetics + cold drinks" scenarios, such as fruit tea, milk tea, juice (high transparency to showcase layering and color), carbonated beverages (high barrier properties to retain bubbles), and high-end brand packaging (to enhance visual texture); suitable for juice bars, specialty coffee shops (cold drink lines), and events such as Ramadan/Hajj (cold drink demand in the Middle East market).
• PP plastic water cups: Primarily designed for "heat-resistant + practical" applications, such as hot coffee, hot tea, and hot soup (withstanding 100-130°C), reusable in homes/offices (wear-resistant, microwaveable), and for yogurt/condiment packaging (acid and alkali resistant); suitable for fast-food chains, coffee shops (hot beverage lines), hotel dairy departments (Middle East market), and laboratories (chemical resistance).

6.2 Market Positioning Differences

• PET: High-end quality oriented, accounting for over 30% of the global plastic packaging market share, irreplaceable in transparent packaging and carbonated beverage fields; higher unit price (due to higher processing costs), but premium pricing is possible in the high-end market, suitable for brands that prioritize appearance and quality (such as high-end juices, specialty coffee), with a higher market share in developed regions.
• PP: Practical and cost-effective oriented, low cost and excellent heat resistance, suitable for price-sensitive scenarios (fast food, takeout); dominates the hot beverage packaging market, strong demand in developing regions, and brand positioning leans towards economy and environmental friendliness (such as chain fast food restaurants, mass-market coffee shops). 

6.3 Selection Decision Matrix

Selection Dimension	PET Plastic Water Cup Advantages	PP Plastic Water Cup Advantages	Scenario Suggestions
Transparency Requirements	★★★★★	★★☆☆☆	Choose PET for displaying contents; otherwise, choose PP
Heat Resistance Requirements	★★☆☆☆	★★★★★	Choose PP for hot drinks (>70℃), choose PET for cold drinks
Environmental Friendliness Requirements	★★★★☆	★★★☆☆	Choose PET for emphasis on recycling, choose PP for emphasis on bio-based materials
Cost Control	★★★☆☆	★★★★★	Choose PP for budget sensitivity, choose PET for quality orientation
Reusability	★☆☆☆☆	★★★★★	Choose PP for repeated use
Barrier Properties	★★★★★	★★☆☆☆	Choose PET for carbonated drinks/juices
Processing Difficulty	★★☆☆☆	★★★★★	Choose PP for complex shapes, choose PET for high precision
Printing Effect	★★★★☆	★★★☆☆	Choose PET for high-quality printing

 

7. Summary

• Material Characteristics: PET's core advantages are high transparency and high gas barrier properties, but its heat distortion temperature is only 70℃, making it only suitable for cold drinks; PP features high heat resistance (100-130℃, microwaveable) and flexibility (resistant to 10⁶ bending cycles), but has lower transparency and average barrier properties. The differences in molecular structure determine the core application scenarios of the two.
• Cost-Effectiveness: PP has better overall cost-effectiveness – although the raw material price is slightly higher than PET, it has lower density (less material used for the same volume), lower processing energy consumption (melting temperature 160℃ vs. PET 245℃), and lower transportation costs; PET is only cost-competitive in large-scale production (enjoying volume discounts) or high-end scenarios (allowing for premium pricing), and its cost advantage will gradually become more prominent after rPET technology matures.
• Environmental Performance: PET boasts significant recycling advantages, with a global recycling rate of 50-60% (compared to only 20% for PP). Technologies such as enzymatic depolymerization and closed-loop depolymerization can increase the recycling rate to over 92%, making it easier to meet mandatory recycled content requirements in regions like the EU and China. PP recycling faces challenges such as molecular degradation and downcycling, and although there have been technological breakthroughs like PureCycle, its environmental suitability remains weaker than PET in the short term.
• Processing and Application: PET relies on injection molding, stretching, and blow molding processes (high precision but high equipment investment), making it suitable for high-end transparent packaging. PP offers flexible processing (thermoforming/injection molding), with a lower processing threshold, making it suitable for practical applications such as hot beverages and reusable containers. Both materials have their own advantages and disadvantages in secondary processing, such as printing and coating (PET requires no pre-treatment, while PP requires corona treatment).